24 TRANSPORTATION RF,SEARCH RF,CORD 1433 Effect of With-Flow Bus Lanes on Bus Travel Times AMER 5. 5HALABY AND RICHARD M. SOBERMAN Improvements in bus performance due to introduction of reserved bus in total travel time ranged from 0 to 15 percent, 5 to 25 percent, lanes have traditionally been evaluated in terms of savings in total and 7 percent, respectively (2). Discrepancies in the results of travel time. Little attention is usually paid to changes in individual these and other studies provide few guidelines for the expected segment times (i.e., travel times between consecutive bus stops along the bus route). An approach is presented that investigates the •effect change since, generally, the overall evaluations do not examine of an urban reserved bus lane on bus travel time on individual seg­ the impact on individual segments (i.e., sections between consec­ ments. Subsequently, the change in segment time is related to char­ utive bus stops). An extensive overview of bus priority experi­ acteristics and traffic regulations at respective segments. Data were ences in North American and European cities is presented else­ obtained by analysis of videotapes recorded before and after the in­ where (2,4). troduction of exclusive curb bus lanes on a major arterial road in In this study, the impact of with-flow bus lanes is investigated downtown Toronto. The data indicate that time savings are most likely to occur on segments where buses previously experienced consider­ by analyzing segments of a bus route individually. An attempt is able congestion, as well as at traffic signals, especially when bus stops made to relate changes in any one segment to traffic regulations are arranged with one on the near side and the next on the far side and characteristics of the particular segment. of their respective intersections. However, these time savings generate To study the effect of with-flow bus lanes on travel times, it is additional ridership, resulting in longer dwell times at stops and a essential to analyze conditions both before and after implemen­ corresponding overall increase in total travel time. Thus, the percep­ tation of the priority scheme. This can be accomplished by pre­ tion of transit service improvement may have more impacts on rider­ ship change than any substantive change in performance. The results paring time-space tables from which travel times for each segment of the study suggest opportunities for using reserved bus lanes on a can then be extracted. In obtaining the comparison results, statis­ more selective basis along a particular route and the need to reconsider tical tests should be used to determine whether the difference is whether taxis should be permitted to use these lanes. significant or whether the change could have occurred simply be­ cause of inherent variations. This is the approach used in com­ paring before and after observations for the Bay Street Urban Throughout North America, reduced dependence on public transit Clearway in Toronto. has led to increased road congestion with corresponding delays and costs. For example, the daily cost of delay in the United States in 1984, on the freeway system alone, is estimated to have ex­ ceeded $1.2 billion (1). By contrast, for any reasonable load fac­ BAY STREET URBAN CLEARWAY AND DATA tor, buses contribute relatively little to congestion. According to COLLECTION one study, a bus can carry 20 times as many passengers as a car and contributes only 3 times as much to congestion (2). As a Street and Service Characteristics result, bus priority schemes have attracted attention as a means of reducing bus delays due to traffic congestion in order to enhance Bay Street, one of the central corridors in downtown Toronto, the attractiveness of transit. extends north-south from Davenport Road to Queens Quay, as Although there are a variety of bus priority schemes, this paper shown in Figure 1. There are two lanes in each direction. Transi is concerned with urban streets along which curb lanes are devoted service consists of two overlapping bus routes, a main route sup­ to bus use, referred to as "with-flow bus lanes." The implemen­ plemented by a "short tum" route during morning and evenin tation of such preferential treatment is generally believed to result peak periods. In the morning period, most riders board buses a in an improvement in total bus travel time, taken as the best single Bloor Street, transferring from the subway to access employmen indicator of level of service. Previous applications of with-flow activities to the south. In the afternoon, the direction of flo bus lanes have shown a wide range of changes in total travel time. reverses. For example, a dual-width exclusive bus lane was introduced Most of the 17 bus stops covered by the service are located o on Madison Avenue in midtown Manhattan and before and after near sides of signalized intersections, and a few are located on fa observations were obtained for the entire length of this facility sides (Figure 2). Throughout this paper, bus stops are by defaul (3). During the p.m. peak hour, average total travel time decreased located on near side (at traffic signals), unless otherwise stated. by 45 percent, from approximately 18 min to less than 10 min. Canadian examples include bus lanes on Albert/Slater and Rideau streets in Ottawa and Eglinton Avenue in Toronto, where changes Project Implementation Department of Civil Engineering, University of Toronto, 35 St. George On October 29, 1990, the city of Toronto initiated the dedicatio Street, Toronto, Ontario MSS 1A4 Canada. of curb lanes to buses, taxicabs, right-turning vehicles, and bicy Bloor Street Front Street miles LA K E Sec A FIGURE 1 Bay Street in metropolitan Toronto. 26 TRANSPOR'IATION RESEARCH RECORD 1433 Data Collection Data were collected by continuous on-board.video camera filming through the bus windshield. The camera is equipped with a stop­ watch that indicates elapsed time, thereby allowing the travel time by segment to be determined. Before implementation, the operation of traffic control devices (i.e., tum prohibitions and parking) .varied throughout the day. Traffic flows and ridership also vary by time of day, as well as by directfon. For these reasons, filming was carried out both be­ fore and after implementation at three fixed times, namely, 8:00 a.m., 2:00 p.m., and 4:30 p.m., to represent the morning peak, off­ peak, and evening peak periods, respectively. For each period, one southbound and one northbound trip were filmed per day. Filming was carried out on Tuesdays, Wednesdays, and Thursdays to avoid irregularities usually associated with weekends, Mondays, and Fri­ days. The sample sizes for the before and after periods are pre­ sented in Table 1. Data Preparation T bus stop From the data collected, each of the southbound and northbound trips during the three periods (i.e., morning, off-peak, and eve­ • traffic signal ning), before and after project implementation, was separated into FIGURE 2 Illustration of segments with different bus stop . individual dwell times (at each stop), individual travel times from locations. each stop and/or traffic signal to the following stop and/or traffic signal, and individual signal times (i.e., delay time at each traffic signal). Finally, the data were entered for computer analysis. des. The project is documented by the Department of Public Works (5) and summarized as follows: ANALYSIS OF AGGREGATE TIMES 1. Almost 3 km of the southbound and northbound curb lanes on the Bay Street are reserved for public transit motor vehicles, Before turning to the detailed analysis of segment times, this sec­ taxicabs, right-turning vehicles, and bicycles only from 7:00 a.m. tion examines the change in bus performance on the basis of total to 7:00 p.m. except on Saturdays, Sundays, and public holidays. travel time. Total travel time for a southbound trip is defined as Seventeen bus stops in each direction are served by the reserved the time from the moment that doors open at the Bloor bus stop lanes. There is no break during the off-peak period because bus to allow for passenger boarding and alighting until the moment delays during this period are of the same order as those during that doors are closed at the Union Station bus stop in the south. the afternoon peak period (5). Most origins and destinations of passenger trips lie along this 2. Stopping, except for transit vehicles, is prohibited from 7:00 section. Total travel time for a northbound trip is defined similarly. a.m. to 7:00 p.m. except on Saturdays, Sundays, and public holi­ Total travel time includes total running and total dwell times. days. Parking is prohibited at all times on both sides of Bay Street. The change in total running time is considered a better measure Stopping was permitted before implementing this project at all of change in overall performance than total travel time because times, but parking was permitted during off-peak periods only. total travel time may increase because of increases in dwell time 3. Some new tum prohibitions were introduced. attributable to increased ridership (which itself, of course, is a 4. The reserved lanes are identified by overhead signs and pave­ positive result). ment markings of white painted diamonds with the message 7 To study the change in any of these three time measures after A.M.-7 P.M., MON-FRI, NO CARS-TRUCKS. project implementation, the t-test on two population means is TABLE 1 Sizes of Before and After Samples Number of Trips Morning Mid-day Evening Period SB0 NB SB NB SB NB 'Before' 16 13 8 7 14 14 'After' 12 12 IO 9 7 IO 0 SB = Southbound; NB = Northbound.